bgp/rib-impl/src/main/java/org/opendaylight/protocol/bgp/rib/impl/BGPSessionNegotiator.java

   1 /*
   2  * Copyright (c) 2013 Cisco Systems, Inc. and others.  All rights reserved.
   3  *
   4  * This program and the accompanying materials are made available under the
   5  * terms of the Eclipse Public License v1.0 which accompanies this distribution,
   6  * and is available at http://www.eclipse.org/legal/epl-v10.html
   7  */
   8 package org.opendaylight.protocol.bgp.rib.impl;
   9
  10 import com.google.common.annotations.VisibleForTesting;
  11 import com.google.common.base.Preconditions;
  12
  13 import io.netty.channel.Channel;
  14 import io.netty.util.Timeout;
  15 import io.netty.util.Timer;
  16 import io.netty.util.TimerTask;
  17 import io.netty.util.concurrent.Promise;
  18
  19 import java.util.List;
  20 import java.util.concurrent.TimeUnit;
  21
  22 import javax.annotation.concurrent.GuardedBy;
  23
  24 import org.opendaylight.protocol.bgp.parser.AsNumberUtil;
  25 import org.opendaylight.protocol.bgp.parser.BGPDocumentedException;
  26 import org.opendaylight.protocol.bgp.parser.BGPError;
  27 import org.opendaylight.protocol.bgp.parser.BGPSessionListener;
  28 import org.opendaylight.protocol.bgp.rib.impl.spi.BGPSessionPreferences;
  29 import org.opendaylight.protocol.framework.AbstractSessionNegotiator;
  30 import org.opendaylight.protocol.util.Values;
  31 import org.opendaylight.yang.gen.v1.urn.ietf.params.xml.ns.yang.ietf.inet.types.rev100924.AsNumber;
  32 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Keepalive;
  33 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.KeepaliveBuilder;
  34 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Notify;
  35 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.NotifyBuilder;
  36 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.Open;
  37 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.OpenBuilder;
  38 import org.opendaylight.yang.gen.v1.urn.opendaylight.params.xml.ns.yang.bgp.message.rev130919.open.BgpParameters;
  39 import org.opendaylight.yangtools.yang.binding.Notification;
  40 import org.slf4j.Logger;
  41 import org.slf4j.LoggerFactory;
  42
  43 public final class BGPSessionNegotiator extends AbstractSessionNegotiator<Notification, BGPSessionImpl> {
  44     // 4 minutes recommended in http://tools.ietf.org/html/rfc4271#section-8.2.2
  45     protected static final int INITIAL_HOLDTIMER = 4;
  46
  47     /**
  48      * @see <a href="http://tools.ietf.org/html/rfc6793">BGP Support for 4-Octet AS Number Space</a>
  49      */
  50     private static final int AS_TRANS = 23456;
  51
  52     @VisibleForTesting
  53     public enum State {
  54         /**
  55          * Negotiation has not started yet.
  56          */
  57         Idle,
  58         /**
  59          * We have sent our Open message, and are waiting for the peer's Open message.
  60          */
  61         OpenSent,
  62         /**
  63          * We have received the peer's Open message, which is acceptable, and we're waiting the acknowledgement of our
  64          * Open message.
  65          */
  66         OpenConfirm,
  67         /**
  68          * The negotiation finished.
  69          */
  70         Finished,
  71     }
  72
  73     private static final Logger LOG = LoggerFactory.getLogger(BGPSessionNegotiator.class);
  74     private final BGPSessionPreferences localPref;
  75     private final BGPSessionListener listener;
  76     private final AsNumber remoteAs;
  77     private final Timer timer;
  78
  79     @GuardedBy("this")
  80     private State state = State.Idle;
  81
  82     @GuardedBy("this")
  83     private BGPSessionImpl session;
  84
  85     public BGPSessionNegotiator(final Timer timer, final Promise<BGPSessionImpl> promise, final Channel channel,
  86             final BGPSessionPreferences initialPrefs, final AsNumber remoteAs, final BGPSessionListener listener) {
  87         super(promise, channel);
  88         this.listener = Preconditions.checkNotNull(listener);
  89         this.localPref = Preconditions.checkNotNull(initialPrefs);
  90         this.remoteAs = Preconditions.checkNotNull(remoteAs);
  91         this.timer = Preconditions.checkNotNull(timer);
  92     }
  93
  94     @Override
  95     protected void startNegotiation() {
  96         Preconditions.checkState(this.state == State.Idle);
  97         int as = this.localPref.getMyAs().getValue().intValue();
  98         // Set as AS_TRANS if the value is bigger than 2B
  99         if (as > Values.UNSIGNED_SHORT_MAX_VALUE) {
 100             as = AS_TRANS;
 101         }
 102         this.sendMessage(new OpenBuilder().setMyAsNumber(as).setHoldTimer(this.localPref.getHoldTime()).setBgpIdentifier(
 103                 this.localPref.getBgpId()).setBgpParameters(this.localPref.getParams()).build());
 104         this.state = State.OpenSent;
 105
 106         final Object lock = this;
 107         this.timer.newTimeout(new TimerTask() {
 108             @Override
 109             public void run(final Timeout timeout) {
 110                 synchronized (lock) {
 111                     if (BGPSessionNegotiator.this.state != State.Finished) {
 112                         BGPSessionNegotiator.this.sendMessage(buildErrorNotify(BGPError.HOLD_TIMER_EXPIRED));
 113                         negotiationFailed(new BGPDocumentedException("HoldTimer expired", BGPError.FSM_ERROR));
 114                         BGPSessionNegotiator.this.state = State.Finished;
 115                     }
 116                 }
 117             }
 118         }, INITIAL_HOLDTIMER, TimeUnit.MINUTES);
 119     }
 120
 121     @Override
 122     protected synchronized void handleMessage(final Notification msg) {
 123         LOG.debug("Channel {} handling message in state {}", this.channel, this.state);
 124
 125         switch (this.state) {
 126         case Finished:
 127         case Idle:
 128             this.sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 129             return;
 130         case OpenConfirm:
 131             if (msg instanceof Keepalive) {
 132                 negotiationSuccessful(this.session);
 133                 LOG.info("BGP Session with peer {} established successfully.", this.channel);
 134             } else if (msg instanceof Notify) {
 135                 final Notify ntf = (Notify) msg;
 136                 negotiationFailed(new BGPDocumentedException("Peer refusal", BGPError.forValue(ntf.getErrorCode(), ntf.getErrorSubcode())));
 137             }
 138             this.state = State.Finished;
 139             return;
 140         case OpenSent:
 141             if (msg instanceof Open) {
 142                 final Open openObj = (Open) msg;
 143                 handleOpen(openObj);
 144                 return;
 145             }
 146             break;
 147         }
 148
 149         // Catch-all for unexpected message
 150         LOG.warn("Channel {} state {} unexpected message {}", this.channel, this.state, msg);
 151         this.sendMessage(buildErrorNotify(BGPError.FSM_ERROR));
 152         negotiationFailed(new BGPDocumentedException("Unexpected message", BGPError.FSM_ERROR));
 153         this.state = State.Finished;
 154     }
 155
 156     private static Notify buildErrorNotify(final BGPError err) {
 157         return new NotifyBuilder().setErrorCode(err.getCode()).setErrorSubcode(err.getSubcode()).build();
 158     }
 159
 160     private void handleOpen(final Open openObj) {
 161         final AsNumber as = AsNumberUtil.advertizedAsNumber(openObj);
 162         if (!this.remoteAs.equals(as)) {
 163             LOG.warn("Unexpected remote AS number. Expecting {}, got {}", this.remoteAs, as);
 164             this.sendMessage(buildErrorNotify(BGPError.BAD_PEER_AS));
 165             negotiationFailed(new BGPDocumentedException("Peer AS number mismatch", BGPError.BAD_PEER_AS));
 166             this.state = State.Finished;
 167             return;
 168         }
 169
 170         final List<BgpParameters> prefs = openObj.getBgpParameters();
 171         if (prefs != null && !prefs.isEmpty()) {
 172             if (!prefs.containsAll(this.localPref.getParams())) {
 173                 LOG.info("BGP Open message session parameters differ, session still accepted.");
 174             }
 175             this.sendMessage(new KeepaliveBuilder().build());
 176             this.session = new BGPSessionImpl(this.timer, this.listener, this.channel, openObj, this.localPref.getHoldTime());
 177             this.state = State.OpenConfirm;
 178             LOG.debug("Channel {} moved to OpenConfirm state with remote proposal {}", this.channel, openObj);
 179             return;
 180         }
 181
 182         this.sendMessage(buildErrorNotify(BGPError.UNSPECIFIC_OPEN_ERROR));
 183         negotiationFailed(new BGPDocumentedException("Open message unacceptable. Check the configuration of BGP speaker.", BGPError.UNSPECIFIC_OPEN_ERROR));
 184         this.state = State.Finished;
 185     }
 186
 187     public synchronized State getState() {
 188         return this.state;
 189     }
 190 }